This invention relates to a laser beam delivery method and system and more particularly to transmission of laser energy through a fiber optic at pcwer levels high enough for manufacturing purposes.
Typically, laser beam delivery for material processing is accomplished through the use of an ensemble of mirrors and prisms for beam steering. An increase in beam steering flexibility is possible when a laser beam is passed through a fiber optic. This flexibility enhances the access to difficult locations on a workpiece during manufacture. Such material processing as drilling, cutting, welding, and selective heat treating and laser surfacing is possible with the laser remote from the workstation.
Laser energy has been transferred along a fiber optic for the purpose of laser communications and laser surgery in the medical field. In both cases, the laser beam is a continuous wave (CW) and average power levels of 100 watts have not been exceeded. As much as 20 watts of CW power from a CO.sub.2 laser, which has a 10.6 micrometer wavelength in the far infrared, have been transmitted through a fiber optic. The 100 watt CW power level was achieved from a laser that has a 1.06 micrometer wavelength in the near infrared. Only the CO.sub.2 laser has been used with a fiber optic for material processing with applications such as engraving and cloth cutting. The average or peak powers are not sufficient for welding, cutting, drilling, and heat treating metals at cost effective rates. The CO.sub.2 laser fiber optic which is composed of thallous bromide and thallous iodide is capable of 55 percent transmittance at 10.6 micrometers, and because of this level of transmissivity requires cooling. The neodymium-yttrium aluminum garnet laser, a source of 1.06 micrometer wavelength energy, has provided the 100 watt CW average power for surgical applications. Such power levels are adequate for limited metal processing but have not been applied. Peak powers in excess of 1000 watts would be more desirable for metal processing.